The processing of gustatory information by neurons in the hamster central nervous system will be studied using both electrophysiological and behavioral techniques. Neurons in the nucleus tractus solitarius, parabrachial nucleus, and thalamus that respond to gustatory stimuli will be examined for their responsiveness to a variety of stimuli and stimulus mixtures. Concurrently with this electrophysiological recording, behavioral exeriments will be conducted to determine how hamsters categorize these gustatory stimuli so that the neurophysiological data can be interpreted within this psychophysical framework. An attempt will also be made to obtain electrophysiological data from taste-responsive neurons in a chronic, behaving hamster preparation. The time course of the neural response to taste stimulation will be of particular interest, particularly in the behaving preparation.